foetal growth Flashcards

1
Q

Best way to check pregnancy stage

A

Symphysis Fundal Height (SPH). identifies the distance between the pubic symphysis and the top of the uterus

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2
Q

What can cause increased or decreased SPH

A

Values that are lower than they should may result from: wrong last menstrual period date, the baby in a transverse lie, or complications including oligohydramnios (low levels of amniotic fluid) or a baby that is small for gestational age (SGA).

Higher values may also be found, due to: wrong last menstrual period date, multiple pregnancy, or maternal obesity.

Complications could include molar pregnancy, fibroids, polyhydramnios or a baby that is large for gestational age (LGA).

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3
Q

What two components contribute to foetal size

A

Genetic and substrate availability

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4
Q

What are the four parameters to determine foetal growth

A

Biparietal diameter (BPD), Head Circumference (HC), Abdominal Circumference (AC) and Femur Length (FL). They are combined to give the Estimated Fetal Weight (EFW).

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5
Q

What is the rate of growth at 15 weeks, 20 weeks, 34 weeks and after 34 weeks

A

14-15 wks: 5g /day

20 wks: 10 g/day

32-34 wks: 30-35g/day

> 34 wks: growth rate decreases

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6
Q

Three phases of foetal growth

A

Cellular hyperplasia (increased cell numbers): 4-20 weeks

Hyperplasia and hypertrophy (increased cell size): 20-28 weeks

Hypertrophy dominates: 28-40 weeks

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7
Q

Why is last menstrual period unelaiable

A

Irregular length of periods; abnormal endometrial bleeding; the use of oral contraceptives; breastfeeding

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8
Q

Why is dating a pregnancy important

A

pregnancy being inappropriately identified as Large or Small for gestational age. Clinical decisions about delivery timings and methods (induction or Caesarean section) may not be correct; glucocorticoids are given prior to preterm delivery to enhance lung surfactant production and subsequent lung function.

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9
Q

Best way to date a pregnancy

A

Ultrasound

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10
Q

How does weed affect foetal growth

A

slow the fetal growth rate and can result in premature delivery. It can also lead to low birth weight, a shortened gestational period and complications in delivery.

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11
Q

How does heroin affect foetus

A

cause interrupted fetal development, stillbirths, and can lead to numerous birth defects. Heroin can also result in premature delivery, creates a higher risk of miscarriages, result in facial abnormalities and head size, and create gastrointestinal abnormalities in the fetus. There is an increased risk for SIDS, dysfunction in the central nervous system, and neurological dysfunctions including tremors, sleep problems, and seizures. The fetus is also put at a great risk for low birth weight and respiratory problems

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12
Q

How does cocaine affect foetus

A

Cocaine use results in a smaller brain, which results in learning disabilities for the fetus. Cocaine puts the fetus at a higher risk of being stillborn or premature. Cocaine use also results in low birthweight, damage to the central nervous system, and motor dysfunction.

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13
Q

How does alcohol affect foetus

A

CNS defects, mental retardation, facial abnormalities, major organ defects, miscarriage, Foetal Alcoholic Syndrome

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14
Q

How does smoking affect foetus

A

fetus is exposed to nicotine, tar, and carbon monoxide. Nicotine results in less blood flow to the fetus because it constricts the blood vessels. Carbon monoxide reduces the oxygen flow to the fetus. The reduction of blood and oxygen flow results in stillbirth, low birth weight, and ectopic pregnancy. There is an increase of risk of sudden death syndrome (SIDS) in infants.

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15
Q

How does gender affect birth weight

A

boys > Girls

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16
Q

How does 2nd pregnancy compare to first

A

second heavier

17
Q

How does insulin affect foetus

A

Increase cell proliferation and nutrient availability

18
Q

How does cortisol affect foetus

A

alter gene transcription, and cell differentiation

19
Q

IGF 1 vs IGF 2

A

IGF 1 has little role in foetal growth is more dominated by 2

20
Q

Role of prenatal glucocorticoids?

A

Tissue differentiation, lung surfactant, intestines (enzyme maturation), acts with thyroxine to mature lungs and nervous system

21
Q

Name some other factors affecting growth

A

EGF, FGF, TGF, interleukin 1, embryonic cholinesterase

22
Q

Define SGA

A

The infant has a birth weight <10th centile (also called ‘Small for dates’).

23
Q

Define IUGR

A

Failure of the infant to achieve its predetermined (genetic) potential for a variety of reasons.

24
Q

Define LBW

A

Less than 2,500g at delivery. Currently ~7% of live births (UK).

25
Q

Define VLBW

A

Less than 1,500g at delivery. Currently ~1% of live births (UK).

26
Q

Define ELBW

A

Less than 1,000g at delivery. Currently ~0.2% of live births (UK).

27
Q

Why does birthweight matter

A

Infants who are inappropriately small at delivery are at increased risk of a range of neonatal complications.

28
Q

What are short term effects of IUGR

A
Respiratory distress
Intraventricular haemorrhage
Sepsis
Hypoglycaemia
Necrotising enterocolitis
Jaundice
Electrolyte imbalance
29
Q

What are medium term effects of IUGR

A

Respiratory problems
Developmental delay
Special needs schooling

30
Q

What are long term effects of IUGR

A

Foetal programming

31
Q

When is IUGR usually encountered

A

2nd and 3rd trimester

32
Q

List maternal factors affecting IUGR

A
Chronic hypertension
Connective tissue disease
Severe chronic infection
Diabetes mellitus
Anaemia
Uterine abnormalities
Maternal malignancy
Pre-eclampsia
Thrombophilic defects
33
Q

List some maternal behavioural factors affecting IUGR

A
Smoking
Low booking weight (<50 kg)
Poor nutrition
Age <16 or >35 years at delivery
Alcohol
Drugs
High altitude
Social deprivation
34
Q

List some foetal factors affecting IUGR

A
Multiple pregnancy
Structural abnormality
Chromosomal abnormalities
Intrauterine (congenital) infection
Inborn errors of metabolism
35
Q

List some placental factors affecting IUGR

A
Impaired trophoblast invasion
Partial abruption or infarction
Chorioamnionitis
Placental cysts
Placenta praevia
36
Q

Why does pre-ecclampsia cause IUGR

A

the main cause of pre-eclampsia is diminished remodelling of the spiral arteries by cytotrophoblast
which causes decreased blood flow and hence decreased nutrient supply to the placenta and fetus.

37
Q

define pre-ecclampsia

A

gestational hypertension of at least 140/90 mmHg on two separate occasions ≥4 hours apart

38
Q

Signs of pre-ecclampsia

A

proteinuria of at least 300 mg in a 24-hour collection of urine, arising de novo after the 20th week of gestation in a previously normotensive woman and resolving completely by the 6th postpartum week.